RESUMEN
The structure, abundance and location of repetitive DNA sequences on chromosomes can characterize the nature of higher plant genomes. Here we report on three new repeat DNA families isolated from Anemone hortensis L.; (i) AhTR1, a family of satellite DNA (stDNA) composed of a 554-561 bp long EcoRV monomer; (ii) AhTR2, a stDNA family composed of a 743 bp long HindIII monomer and; (iii) AhDR, a repeat family composed of a 945 bp long HindIII fragment that exhibits some sequence similarity to Ty3/gypsy-like retroelements. Fluorescence in-situ hybridization (FISH) to metaphase chromosomes of A. hortensis (2n = 16) revealed that both AhTR1 and AhTR2 sequences co-localized with DAPI-positive AT-rich heterochromatic regions. AhTR1 sequences occur at intercalary DAPI bands while AhTR2 sequences occur at 8-10 terminally located heterochromatic blocks. In contrast AhDR sequences are dispersed over all chromosomes as expected of a Ty3/gypsy-like element. AhTR2 and AhTR1 repeat families include polyA- and polyT-tracks, AT/TA-motifs and a pentanucleotide sequence (CAAAA) that may have consequences for chromatin packing and sequence homogeneity. AhTR2 repeats also contain TTTAGGG motifs and degenerate variants. We suggest that they arose by interspersion of telomeric repeats with subtelomeric repeats, before hybrid unit(s) amplified through the heterochromatic domain. The three repetitive DNA families together occupy approximately 10% of the A. hortensis genome. Comparative analyses of eight Anemone species revealed that the divergence of the A. hortensis genome was accompanied by considerable modification and/or amplification of repeats.
Asunto(s)
Anemone/genética , Cromosomas de las Plantas/genética , ADN Satélite/genética , Variación Genética , Filogenia , Secuencia de Bases , Southern Blotting , Clonación Molecular , Heterocromatina/genética , Hibridación Fluorescente in Situ , Datos de Secuencia Molecular , Polimorfismo de Longitud del Fragmento de Restricción , Análisis de Secuencia de ADN , Especificidad de la Especie , Telómero/genéticaRESUMEN
The aim of this study was to investigate the safety and efficacy of the two most commonly practiced temporary sympathectomy techniques in the treatment of chronic refractory angina. Fifty-nine consecutive refractory angina patients commencing outpatient temporary sympathectomy from November 1, 2000 to November 1, 2002, were prospectively audited for duration of pain relief and procedural complications over a two-year period. A total of 227 stellate ganglion blockades (SGB) and 100 paravertebral blockades (PVB) were performed on 59 chronic refractory angina (CRA) patients naïve to sympathectomy. The mean period of pain relief obtained following SGB was 3.48 weeks (SD 3.38) and the mean relief following PVB was 2.80 weeks (SD 2.00). Mild, fully reversible complications occurred in 3% of SGB and 3% of PVB procedures, with one patient requiring overnight hospitalization. This study demonstrates that temporary sympathectomy may provide a safe and effective outpatient procedure in refractory angina patients when applied as part of holistic care.